A human-readable representation of a possible destination for a payment, similar to an email address. Unlike an email address however, there are a variety of address types, and most addresses are intended only for a single use. This is because addresses represent not only the destination of a payment, but constraints required to redeem funds. For the most common type of address, the constraints require that the recipient provide both the public key which hashes to the requisite hash and a valid signature that is created from the corresponding private key. Other address types require signatures from multiple parties (multi-sig), signatures created within specified time limits, or other more complex constraints.

A reward (in DCR) split between PoW miners, active and chosen voters, and the Treasury for successfully creating a block of transactions. The block reward decays exponentially with block height (length of blockchain). However, Decred’s algorithm interpolates this decay over time so as not to produce market shocks, as typically seen in algorithms that involve large and infrequent reductions, such as halving the rewards every 4 years. The block reward started at 31.19582664 and it adjusts every 6,144 blocks (approximately 21.33 days) by reducing by a factor of 100/101.

In each block, five tickets are called to vote. In addition to votes on any open consensus rule change proposals, each ticket votes to approve or reject the regular transaction tree of the previous block. If a majority of voting tickets vote Yes, the regular transaction tree of the previous block is accepted. If a majority of voting tickets vote No (or there is a tie), the regular transaction tree of the previous block is rejected and those transactions are returned to the mempool.

A transaction is confirmed when it has been included in a block that has been verified by the network (added to the blockchain). Each additional block added to the blockchain reconfirms all transactions in all previous blocks. The number of times a transaction has been confirmed is used as a measure of confidence that the transaction will remain in the blockchain. A wallet or other service may require a certain number of confirmations before it considers a transaction to be valid. For example, if a wallet requires three confirmations to consider a transaction valid, it would require the next two blocks after the block including the transaction to confirm the transaction.

Rules, encoded in software, that allow a network of nodes to reach an agreement about the state of the ledger. Rules include what data blocks can contain, how block data is structured, and how nodes validate blocks.

Difficulty is a measure of how difficult it is to mine a new block (i.e. find a hash below a given target). In Decred, the PoW difficulty is calculated from the exponentially weighted average of differences in previous block times.

The output of a cryptographic hashing function that produces a fixed-size value from variable-size input. While it is computationally easy to create a hash from an input, it is extremely computationally difficult to calculate an input that will produce a given hash.

In Decred, a hybrid PoW/PoS system is used, whereby blocks mined by PoW miners must be approved by ticket holders, which are pseudorandomly selected from the ticket pool. This provides a check on PoW miners and increases the overall cost of attacking the network. When a block is approved, 60% of the block reward goes to the PoW miner, 30% goes to the holders of tickets called to vote (approve blocks), and 10% goes to the Decred Treasury to fund the project.

A group of miners who share (pool) their computational resources to mine DCR. When a member of a mining pool successfully mines a block, the rewards are typically split among all pool members in proportion to the hashpower they contribute to the pool.

Tickets that have been called but did not receive a reward. This can happen if a ticket is called to vote, but the wallet that bought the ticket does not respond. This can also happen if the wallet does respond and broadcasts its vote to the network, but a miner does not include their vote in the following block.

Orphaned blocks are valid blocks which are not included in the definitive blockchain. Orphan blocks can occur when they are part of a branch of the blockchain that has been abandoned. This can occur naturally when two miners produce blocks at similar times. Orphan blocks can also be created when they build on an unknown block (i.e. the “parent” block is unknown, making it an “orphan”).

A transaction with missing inputs (i.e. the “parent” transaction is unknown, making the transaction an “orphan”). Orphan transactions can also be created when they are part of a block that has been abandoned and have not been included in another block. For example, if a miner creates a valid block with transactions specific to them, such as coinbase transactions and votes, and that block is orphaned, the transactions in that block will become orphaned transactions.

An astronomically large number which, when kept secret from others, enables legitimate spending of personal Decred while preventing others from spending it. Private keys are encrypted by wallets to prevent theft.

An astronomically large number generated algorithmically from a private key. Public keys can be freely shared without revealing any information about the private key they are generated from. The user’s public key is used to prove that a transaction was signed using their private key.

The minimum level of participation required in order for a decision-making process to produce an actionable outcome. Changes to the consensus rules require at least 10% of votes to be for or against the change in order to be valid. Politeia proposals require 20%.

An interval of 8064 blocks (~4 weeks) in which ticket holders can vote on consensus rule changes. A Rule Change Interval (RCI) consists of four Stake Version Intervals (SVI), which are 2016 blocks (~1 week). Once the conditions for a vote have been met during an SVI, voting is scheduled to begin on the first block of the next RCI. Because there are four SVIs per RCI, it can take up to 6048 blocks [3 SVIs] for the next RCI to begin.

A proposal to change the consensus rules of the Decred blockchain. Rule change proposals must be implemented in latent code within the software running the network’s nodes. If the proposal passes, the latent code activates one month later.

A 256-bit (32-byte) cryptographically secure random number that can be used to recover a wallet. When creating a wallet using any Decred wallet software, a 33 word “seed phrase” is also created from the 32-byte seed. If the wallet is lost or corrupted, the seed phrase can be used to restore the wallet’s private keys, transaction history, and balances using any Decred wallet on any computer.

A wallet mode in which only blocks related to addresses owned by the wallet are downloaded. When not in SPV mode, wallets must download all blocks in the blockchain to verify transactions (fully validating mode). SPV mode allows wallets to operate with less stringent hardware requirements and load significantly faster. SPV wallets cannot vote, but can purchase tickets and allocate voting rights to a Voting Service Provider (VSP).

An interval of 2016 blocks (~1 week) which is used to determine if a vote on concensus rules can begin. Before a vote on consensus rule changes can begin, 75% of tickets that vote during a Stake Version Interval (SVI) must be using software that contains the latent software change being proposed.

Decred holders can time-lock DCR in exchange for tickets. Tickets grant their holder the ability to vote, and it is through ticket voting that major governance decisions are made. The DCR locked to buy a ticket is unlocked after that ticket is called to vote on-chain (this averages around one month, maximum around 4 months), along with a reward. Around 0.5% of tickets are not called before they expire; in this case the DCR is un-locked but no reward is granted.

The amount of DCR one must time-lock in order to buy a ticket. The ticket price is algorithmically adjusted with the goal of keeping the ticket pool at an optimal size of 40,960 tickets. The algorithm for setting the ticket price was changed by DCP-0001, the first consensus rules change to be adopted using an on-chain vote.

The process of buying part of a ticket. This is done by coordinating with other parties who will buy the other parts of a ticket. This can be done without giving up custody to your DCR. The minimum amount of DCR that can be put into a split ticket is 5 DCR. Ticket-splitting is currently coordinated through the ‘ticket-splitting’ channel on the Decred slack channel.

A file that stores private keys. Wallets allow their owner to view and create transactions on the blockchain. The Decred team maintains a GUI wallet (Decrediton) and Command Line Interface (CLI) wallet tools for advanced users. Decred is also supported by numerous 3rd party wallets.